Reflection & Mirrors

Recap: Diffuse reflection: gives a blurry image (or none at all) Specular reflection: gives a clear image Mirror types: PLANECONVEXCONCAVE

Plane Mirrors The image formed by plane mirrors can only be seen behind the mirror. This is known as a virtual image. Image is the same size as the object. Only the right and left of the image is changed.

Curved Mirrors Curved mirrors can be either – concave (making a little cave) – Causes light to converge – convex (vexing out in the middle) – Causes light to diverge

Law of Reflection

Ray Diagrams Show path of light from object  mirror  away from mirror Allows you to determine the location and properties of an image formed by a mirror or lens

Ray Diagram: Basic set-up ** r = 2f mirror Principal axis C (center of curvature) F (focal point) f (focal length) r (radius of curvature)

Ray Diagrams: images REAL vs. VIRTUAL UPRIGHT vs. INVERTED SAME SIZE, SMALLER, ENLARGED COMPARE IMAGE TO ORIGINAL OBJECT

Real or Virtual Real images can project on a screen Virtual images can only be seen in a mirror

Upright or Inverted Upright images are oriented the same as the object Inverted images are oriented in the opposite direction as the object

Reduced or Enlarged Reduced images are smaller in size than the object Enlarged images are larger in size than the object

Get ready to draw diagrams… Take 2 different colored pencils Take a slice of index card/Ruler – This will be your straight-edge – PUT YOUR NAME ON IT & KEEP IT – Decorate it if you want to Take a notes packet Ready? Let’s do this!

Concave Mirror A F Step 1: draw horizontal ray from top of object to mirrorStep 2: draw reflected ray from point where ray hits mirror through focal point Step 3: draw second ray from top of object through focal point to mirror Step 4: draw reflected ray from point where ray hits mirror horizontally back Step 5: draw image from principal axis to intersection of reflected rays Image is: REAL INVERTED LARGER FARTHER

Concave Mirror B F Step 1: draw horizontal ray from top of object to mirrorStep 2: draw reflected ray through focal pointStep 3: draw second ray from focal point, through top of object, to mirror Step 4: draw horizontal reflected rayStep 5: continue both reflected rays behind mirror as DASHED LINES Step 6: draw image from principal axis to intersection of reflected rays Image is: VIRTUAL UPRIGHT LARGER FARTHER

Convex Mirror F Step 1: draw horizontal ray from top of object to mirrorStep 2: draw reflected ray from focal point through point where ray hit mirror and out Step 3: draw angled ray, aimed at focal point, to mirrorStep 4: draw horizontal reflected rayStep 5: continue both reflected rays behind mirror as DASHED LINES Step 6: draw image from principal axis to intersection of reflected rays Image is: VIRTUAL UPRIGHT SMALLER CLOSER

Questions? Begin optics packet!